The present invention relates to a fixed displacement suction and exhaust apparatus using coaxial rotary pistons, which can be used for various kinds of compressors, vacuum pumps, fluid transfer pumps or internal combustion engines, and more particularly, to a fixed displacement suction and exhaust apparatus using coaxial rotary pistons, wherein a crank pin of a crankshaft is installed to rotate two rotary pistons at different speeds.
A suction and exhaust apparatus using coaxial rotary pistons refers to a suction and exhaust apparatus having a mechanism in which suction and exhaust functions are performed by a change in the displacement between two rotary pistons by rotating the two rotary pistons at different speeds such that a plurality of suction and exhaust chambers are formed by the two rotary pistons in an annular cylinder to then be rotated along a coaxial line.
Reciprocating piston suction and exhaust apparatuses based on linear motion, which are currently in widespread use, are constructed to alternately actuate suction and exhaust functions by a set of a cylinder and a piston. Thus, whenever suction and exhaust functions are alternately performed, valves must be actuated. Also, when the displacement is increased, many cylinders and pistons are required. Further, since the cylinder of the side connected to a connecting rod is opened, the displacement efficiency is generally below 50%. To solve the above problems, there have been developed fixed displacement suction and exhaust apparatuses wherein two rotary pistons are rotated in an annular cylinder to form suction and exhaust chambers between the pistons.
Japanese Patent Publication No. Hei 5-7524 describes a planetary gear device having a sun gear, a planetary gear and an internal gear engaged in a non-circular gear combination, and a rotary piston suction and exhaust apparatus constructed to make a plurality of rotary pistons revolve at unfixed speeds inside a cylinder in synchronization with unfixed-speed revolution applied to a plurality of planetary shafts by the planetary gear device. In this suction and exhaust apparatus, since a plurality of gears are engaged in a non-circular gear combination to then be rotated, problems may be encountered with precise fabrication of gears and load resistance.
Japanese Patent Laid-open publication No. Hei 8-296401 describes an engine apparatus based on relative motion constructed to rotate a rotary piston at unfixed speeds by connecting the rotary piston to the output shaft provided in the center of a cylinder using a crankshaft. This apparatus rotates the rotary piston by complex inversion driving, in which the rotation force of the output shaft serves as a crankshaft, so that pressure is applied to the crankshaft, thereby disabling to embody the apparatus.
Japanese Patent Publication No. Hei 6-96964 describes a rotary piston engine for performing suction and exhaust functions, wherein an engine shaft coupled to an eccentric shaft acceptor, is connected to a flat shaft, and an external gear provided on the flat shaft and an internal gears provided on a cavity are combined in a ratio of 2:1 by being combined with a cylinder rotating together with the engine shaft, to thus rotate two pistons opposed to each other by a lever fixed to the eccentric shaft. According to this apparatus, since the output shaft and the flat shaft are connected to the eccentric shaft, the connecting portion thereof is liable to damages under high power.
It is an object of the present invention to provide a complex-cycle suction and exhaust apparatus that is easily fabricated due to a simplified structure and has a plurality of suction and exhaust chambers.
The object of the present invention is achieved by a suction and exhaust apparatus according to the present invention, wherein two rotary pistons having a plurality of wing plates for partitioning a cylinder into a plurality of suction and exhaust chambers, are engaged with each other so as to be installed coaxially with cylinder axis lines, the two coaxial rotary pistons are connected to a crank pin of a crankshaft to then be rotated at different speeds, and the spaces between each of the respective wing plates of the two rotary pistons are hermetically sealed to make independent suction and exhaust chambers, thereby performing suction and exhaust functions.
According to the present invention, there is provided a suction and exhaust apparatus including a cylindrical, hermetically sealed housing having supporting holes for supporting a main axis of a crankshaft, formed at both ends, and having an internal gear (or external gear) formed therein, the internal gear having the supporting holes as concentric circles thereof; a piston block having a plurality of wing plates for forming a plurality of independent hermetically sealed chambers formed inside the housing by radially protruding the outer circumference of an annular disk coaxially rotatably installed in the housing to then be hermetically sealed with the inner circumference of the housing, the piston block configured such that two rotary pistons having a connection hook on the inner circumference are engaged with each other while the wing plates cross each other; and a rotation device having a crankshaft installed coaxially with the housing so that the crank pin of the crankshaft is disposed within the annular space in the center of the rotary piston, a connecting rod rotatably connected to the crank pin of the crankshaft, external gears (or internal gears) having a teeth proportion for engagement with internal gears provided on the housing, at both ends of the shaft acceptor of the connecting rod, and two connecting rod elements for independently rotating two rotary pistons by connecting the same with a connecting hook facing the two the rotary pistons, formed at either side of the center of the shaft acceptor of the connecting rod.
The housing of the present invention consists of a cylinder and sealing plates for hermetically sealing both ends of the cylinder, and the sealing plates have a bearing for supporting the crankshaft to be rotated, mounted in a crankshaft hole installed coaxially with the cylinder. The internal gear engaged with the external gear rotating round the crank pin of the crankshaft are installed coaxially with the crankshaft. A suction hole, an exhaust hole and an ignition plug may be further formed in the cylinder according to use of the suction and exhaust apparatus. The internal gear may be mounted by fixing a gear ring, and bearings for supporting rotation of each of two rotary pistons installed inside may also be further installed on the inner surfaces of the two sealing plates.
The piston block includes two rotary pistons having the same shape and rotatably coupled with respect to the contact surface thereof to then independently be rotated, each rotary piston having an annular disk the outer diameter of which is smaller than the inner diameter of the cylinder, a plurality of wing plates radially protruding from the outer circumference of the disk, and a connection hook formed on the inner circumference of the disk. The contact surface of the two rotary pistons is leveled with the cylinder such that it is possible for the two rotary pistons to be rotated relatively in a state in which the two rotary pistons are hermetically sealed, and the outer surfaces thereof are supported by a bearing mounted on the housing to then be rotated, independently. In the radial wing plates of the rotary pistons, the axial widths thereof are the same as those of the rotary pistons. Thus, one plane of each wing plate is positioned on the same plane with one plane of the integrally formed rotary piston, and the opposite plane thereof is positioned on the same plane with the opposite outer plane of the piston coupled thereto, so that both planes of the wing plate of the rotary piston are hermetically sealed to the inner surface of the sealing plates. Also, the outer-end surface of the wing plates rotates within the cylinder in a state in which it is hermetically sealed to the inner surface of the cylinder. Reinforcement feet are preferably formed in the front and rear of the fixing parts of the wing plates for the purpose of enhancing the fixing strength when the reinforcement feet cross each other, irrespective of a displacement efficiency. According to the aforementioned configuration, the hermetically sealed spaces for forming a plurality suction and exhaust chambers partitioned by both sides of each of the wing plates of the two rotary pistons and by both sides of the housing, are produced between the outer circumference of the annular disk of each of the rotary pistons and the inner circumference of the cylinder by rotation of the rotary pistons. Floating pin holes for accommodating floating pins for actuating the rotary pistons are formed in the connection hook installed on the inner circumference of the annular disk.
The rotation device of the present invention includes the crankshaft rotatably installed in the center of the housing such that a crank pin of the crankshaft rotates around the central annular space of the rotary piston block, and the connecting rod rotatably coupled with the crank pin of the crankshaft. The connecting rod includes at least one external gear formed coaxially with the pin, at both ends of the shaft acceptor in the center, and two connecting rod elements which rotate the rotary pistons coupled therewith according to rotation of the connecting rod, are radially formed linearly at both sides of the shaft acceptor.
The number of teeth of the external gear of the connecting rod is different from that of the internal gear of the housing such that the internal gear is disposed eccentrically with respect to the external gear. Thus, if the external gear operating with rotation of the crankshaft rotates, the rotation angle of the connecting rod with respect to the center line of two rotary pistons coaxially rotating around the internal gear is changed. Therefore, the two rotary pistons coupled to the respective connecting rod elements rotate at different speeds.
The external gear of the connecting rod coupled to rotate the crank pin of the crankshaft according to the present invention, is engaged with the inner gear mounted on the housing, to rotate the crank pin while rotating with the crankshaft. The rotation angle of two points at which the diameter extending line of the external gear meets on an imaginary circumference formed by the axis core of the crankshaft as a center, periodically changes according to the rotation of the crankshaft. Due to the change in the rotation angle, the angle of wing plates of two rotary pistons which are connected to two linear connecting rod elements and rotate, also changes. Thus, the action in which the space between the wing plates of the two rotary pistons is widened or narrowed, is repeated, thereby performing suction and exhaust functions.
The rotation cycle of each rotary piston depends on the combination of the internal gear fixed on the housing and the external gear and the teeth proportion of the engaged gears. If the number of wing plates for one rotary piston is N, the teeth number of the gear fixed on the housing is N and the gear is the internal gear, then the teeth proportion of the internal gear to the external gear is N:N-1. If the fixed gear is external gear, the teeth proportion of the external gear to the internal gear is N:N+1. For example, in the case of a 8 cycle engine in which the number of wing plates of two rotary pistons is eight, the number of wing plates of each rotary piston is four. Thus, if the gear fixed on the housing is the internal gear, the teeth proportion of the internal gear to the external gear is preferably 4:4-1, that is, 4:3. Also, if the gear fixed on the housing is the external gear, the teeth proportion of the external gear to the internal gear is preferably 4:4+1, that is, 4:5.
In the case of a 6-cycle engine in which the number of wing plates of two rotary pistons is six, if the gear fixed on the housing is the internal gear, the teeth proportion of the internal gear to the external gear is preferably 3:2. Also, if the gear fixed on the housing is the external gear, the teeth proportion of the external gear to the internal gear is preferably 3:4.
In the present invention, the rotation device includes circumferential floating pins rotatably inserted into the connection hook installed within each annular disk of the rotary pistons, so that rotation of rotary pistons and connection with the connecting rod elements can be effectively achieved. Each of the floating pins includes a connection hole into which the connecting rod element of the connecting rod is inserted to move back and forth, at the central portion thereof. Also, the floating pin functions to rotate the main body of each rotary piston by inserting the rotary piston thereinto.
The floating pins are constructed such that they pivotally move within a fan-shaped space of the respective rotary piston so as not to obstruct mutual rotation of the rotary pistons when they are linearly connected by the respective connecting rod elements to then rotate at different speeds. The angles between two rotary pistons and the connecting rod are changed hen the connecting rod rotates eccentrically with respect to the rotary pistons. Thus, the floating pins rotate as the connecting rod elements move back and forth. Also, the floating pins serve to facilitate the rotation of two rotary pistons irrespective of a change in the rotation angle.
According to the aforementioned construction, the connecting rod coupled to the crank pin of the crankshaft rotates all the time on the concentric circle of the axis core of the rotary piston, from the eccentric location with respect to the axis core of the internal gear formed on the housing. Since the teeth number of the external gear of the connecting rod is different from that of the internal gear of the housing, engaged therewith, the respective rotary pistons connected to the two connecting rod elements of the connecting rod, rotate at different speeds depending on a predetermined proportion of teeth numbers, according to the rotation of the crankshaft.
As the two rotary pistons rotate at different speeds, the rotation speeds of the wing plates formed thereon also differ, so that the space between the wing plates of the two rotary pistons repeatedly gets widened or narrowed, thereby performing suction and exhaust functions. In the suction and exhaust apparatus according to the present invention, the number of suction and exhaust chambers can be changed by varying the number of wing plates of each rotary piston, according to use and capacity. For example, in the case of constructing a 4-cycle internal combustion engine, in consideration of uniformity in the load, in order to perform only suction and exhaust functions in which 8 cycles with 4 cycles combined are appropriate, it is more suitably used to repeat 6 cycles 3 times.